It is known in the art that hot fusion laser printing on a substrate such as paper includes the steps of character generation, character transfer to the paper, and subsequent character fusion on the paper. Character fusion by the hot fusion laser printing process creates a permanent image on the paper by heating characters which have been transferred onto the paper. The characters are typically composed of colored, polymeric toner powder. The toner is ordinarily composed of a polymer such as polyester, styrene/acrylate polymer or polyvinyl butyryl resin and a pigment such as carbon black.
In comparison to the hot fusion laser printing process, the known cold fusion process achieves significantly higher printing speeds. The cold fusion process provides a solvent laden vapor zone in which a fusing agent is used to fuse together, and to the paper, toner partides as the paper is passed through the vapor zone. Compositions such as blends of trichlorotrfluoroethane (CFC-113) and acetone as well as dichlorofluoroethane (HCFC-141b) have been used as fusing agents in the cold fusion process. U.S. Pat. No. 5,333,042 teaches a cold fusion method using various hydrochlorofluorocarbons.
However, in recent years, chlorine containing hydrochlorofluorocarbons have proven to be environmentally unacceptable. Therefore, a need exists for environmentally acceptable fusing agents.